Improvement in apparatus for closing doors



H. F. SHAW.

Apparatus for Closing Doors.

Patented August 19, 1873.

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WITNESSES. //v1 EN T01?- AM. PH07U-LIT/1'06RAPH/C 00 M Mommy/iv mums) STATES HENRY F. SHAW, OF WEST ROXBURY, MASSACHUSETTS.

IMPROVEMENT IN APPARATUS FOR CLOSING DOORS.

Specification forming part of Letters Patent No. 141,896, dated August 19, 1873; application filed December 27, 1872.

To all whom it may concern:

Be it known that I, HENRY F. SHAW, of West ltoxbury, in the county of Norfolk and State of Massachusetts, have invented certain new and useful Improvements in Apparatus for Closing Doors, of which the following is a specification:

My invention relates to an automatic device for the noiseless closing of doors; and it consists in the application of a weight to a piston fitted to slide in a cylinder, in combination with a cord and suitable pulleys for guiding the same from the piston to the door to which said cord is attached, said. piston being provided with an inverted flexible cup-packing,

, and so fitted to the cylinder that the air contained in the cylinder below the piston may escape past the piston when it is descending, but not so fast but that the descent of the weight will be retarded, and thereby prevent the slamming of the door, which is invariably the case when the weight is left freeto descend in the open air, and subject to the laws governing falling bodies under like conditions.

Figure l of the drawings is an elevation of the outer side of a door that opens inward,

' showing my closing apparatus attached, with the cylinder in section. Fig. 2 is a sectional plan of the same, the plane of the section being on line as an on Fig. 1; and Fig. 3 is a vertical section of a door and frame on line 2 2 on Fig. 1, and also showing the cylinder in section and provided with a short piston, and a spring applied thereto instead of a weighted piston. I

In the drawings, A is the door, and B the door-frame. O is a metallic cylinder secured f to the door-sill; or it may be secured to the jamb, or it may be inclosed in the jamb or post of the frame, the cylinder being, preferably, placed by the side of, secured to, or inclosed in, the same post of the jamb to which the door is hung. D is a weighted piston, provided with a flexible cup-packing, a, of leather or other suitable material, secured to its lower end, with its turned edges downward, and so fitted to the cylinder as to slide freely therein when it is ascending by virtue of the peculiar form of the packing, which allows the air to enter the chamber under the piston to serve as a retarding element when the piston dc scends, the resistance to the downward motion of the piston presented thereby causing the packing to be forced out against the cylinder, and thereby increase the retarding power by diminishing the area of the passage for the escape of the air; but it is evident" that if the packing was allowed to fit the cylinder air: tight, the piston would not descend at all. I therefore construct my packing with one or more notches or grooves in its outer edge, for the purpose of allowing the air to escape, and thereby permit the piston to descend just fast enough to close the door without slamming it. A cord, 1), is attached to the upper end of the piston, and, passing over and around the pulleys c and d secured to the doorframe, is secured by its other end to the door at c.

In Fig. 3 a modification of the piston may be seen, in which, instead of the long weighted piston D, a short piston is used, secured to the lower end of arod, f, to the upper end of which is secured the cord b. A spiral spring, 9, one

end of which rests upon the piston, and the other end bears against a ring, it, inserted in the top of the cylinder, serves instead of the weight of the long piston.

The operation of my invention is as follows: When the door is opened the piston D is raised in the cylinder 0, the packing a yielding to the downward pressure of the atmosphere, and allowing the air to pass to the under side of the piston. When the hand is removed from the'door the piston D, acted upon by the force of gravity in the case of the long-weighted piston, or by the spring 9 in the case of the short piston, begins to descend; but the air in the cylinderv below the piston, acting as a cushion, retards the descent of the piston, allowing it to fall only so fast as the air is enabled to escape past the packing, and closing the door so gradually as to prevent all slamming, but, at the same time, with sufficient force to latch the door. When the spring is used instead of a weight, the cylinder may be placed in a horizontal position above the door, or in any other desirable position, without affecting the principle of action, viz., the cushion of air behind the piston escaping past it slowly for the purpose of preventing the acceleration of the motion of the ble manner, when constructed and arranged to close the door by the force of gravity, and. prevent the acceleration of the motion of the weight in its descent by the gradual escape of the air from the chamber below the weight,

substantially as herein set forth and described.

Executed at Boston this 21st day of December, 1872.

HENRY F. SHAW. Witnesses:

S. .A. Wool), N. O. LOMBARD. 

